Women who give birth to low weight babies are at increased risk of having a future stillbirth, research shows.

A study by a group from Karolinska University in Sweden found the two could be caused by similar factors.

However experts warn the study, published in the New England Journal of Medicine, should not deter couples from trying for another baby.

Alison MacFarlane of St Bartholomew's School of Nursing and Midwifery said "The absolute risk is still quite low."

Influencing factors

"This study can provide clues for identifying groups of women at increased risk, but shouldn't deter them from considering more children."

The researchers took data of 410,021 women from the national registry who had given birth to two children.

They found women whose first infant was born at term with a low birth weight face two times the risk of having a stillborn in future pregnancies.

For those with a child underweight and premature (at 32 weeks), the rate was five times higher.

The risk

However, the risk of having a stillbirth even in the highest risk group was still relatively low, at under two per cent.

The study concluded that there could be similar factors at play for low weight infants and stillbirths, but they did not determine what these may be.

Dr Phil Baker, Professor of Maternal and Foetal Health at the University of Manchester, said "If someone has a predisposition to having a small baby then it follows that there would be a higher likelihood of the baby dying in the next pregnancy."

Janet Fyle, a midwife at the Royal College of Midwifery, told BBC News Online there were a number of reasons a woman can have a stillbirth or child with foetal growth retardation.

"You have to take into consideration the mother's nutritional state, blood flow, smoking, weight among many other factors," she said.

"There are pointers and indicators that can help clinicians, but sometimes you can't prevent a woman from having a stillbirth."

In UK in 2002, 3727 stillbirths were recorded, a rate of around 5.5 per 1000. The risk faced by women in the highest risk category is around 19 in 1,000.